The network architecture of traditional GSM system is as shown in FIG. 1, and includes three layers, i.e., a core network, a base station controller and a base station. The base station controller and the base station can be collectively known as a base station subsystem. An interface between the core network and the base station controller is known as an A interface; an interface between the base station controller and the base station is known as an Abis interface; and an interface between the base station and the mobile terminal is known as an Um interface. The core network, the base station controller and the base station cooperate to provide a complete mobile voice service function to the mobile terminal.
As technologies evolve, there has been a flat GSM network architecture, and the interface thereof is as shown in FIG. 2. The flat GSM network mainly includes two layers, i.e., a core network and an enhanced base station. An interface between the core network and the enhanced base station is an A interface; an interface between the enhanced base station and the mobile terminal is an Um interface; and a new interface is defined between the enhanced base stations, which is known as an interface between enhanced base stations, and can be used for the interaction between the enhanced base stations. Although the behaviors in the air interface of the network architecture of the traditional GSM system and that of the flat GSM network architecture are the same, one of the advantages of the flat GSM network architecture is that: GSM can use the same architecture as the downward evolution version of High-Speed Packet Access (HSPA) which is also flat, i.e., HSPA+, or a Long Term Evolution (LTE) network to operate on a same spectrum, which will make providers to dynamically share the limited spectrum resources in different wireless technologies, such as GSM, HSPA+ or LTE etc. Thus, a scenario may show that HSPA+ or LTE occupies most of the spectrum resources, while GSM occupies fewer spectrum resources; however, the number of GSM users is not drastically reduced. This requires the GSM network to provide voice services for these users with relatively fewer spectrum resources, thus resulting in a great challenge to the traditional GSM technology.
Since the traditional GSM is a Time Division Multi Access (TDMA) system, the system capacity is limited by Time Slot (TS) resources, and one TS can only carry one Full Rate (FR) voice user or two Half Rate (HR) voice users simultaneously. As technologies evolve, there have been many techniques to improve spectrum utilization efficiency; and Voice services over Adaptive Multi-user channels on One Slot is an example. Voice services over Adaptive Multi-user channels on One Slot allows carrying two FR voice users or four HR voice users on one slot simultaneously, so as to enhance support capacity for voice users without increasing spectrum resources of the whole GSM network.
Using Voice services over Adaptive Multi-user channels on One Slot, the mobile terminal can report support capability for Voice services over Adaptive Multi-user channels on One Slot thereof via the interface between the mobile terminal and the base station subsystem. However, if the mobile terminal does not report support capability thereof due to some reasons such as defects on software design, or although the mobile terminal reports the capability, the base station subsystem desires to know more precise, or more detailed capability for Voice services over Adaptive Multi-user channels on One Slot supported by the mobile terminal, a solution is needed. On one hand, the solution enables the network to automatically detect the support capability for Voice services over Adaptive Multi-user channels on One Slot in the condition that the mobile terminal does not report the support capability for Voice services over Adaptive Multi-user channels on One Slot; on the other hand, the solution enables the base station side system such as the base station subsystem in the traditional GSM network to know more precise, or more detailed capability for Voice services over Adaptive Multi-user channels on One Slot supported by the mobile terminal after the mobile terminal reports it has the capability. However, such solution does not exist in the prior art. Therefore, when this new technology of Voice services over Adaptive Multi-user channels on One Slot is introduced, the base station subsystem cannot acquire the capability of those mobile terminals which do not report the support capability for Voice services over Adaptive Multi-user channels on One Slot, and thus cannot use the technology of Voice services over Adaptive Multi-user channels on One Slot more effectively.